Power system for radio apparatus



H. M. STOLLER.

POWER SYSTEM FOR RADIO APPARATUS.'

APPLICATION FILED APR. 30, 19l8.

Patented Apr. 4, 1922.

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HUG-H STOLLER, OF NEW YORK, N. 'Y., ASSIGNOR TO-WESTERN ELECTRICCOMPANY, INCORPORATED, OF NEW YORK, N. 'Y., A. CORPORATION OF NEW YORK.

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Specification of Letters Patent.

Patented A r..4, 1922.

Application filed April 30, 1918. Serial No. 231,586.-

To all whom it may concern:

Be it known that I, HUGH M. S'roLLnR, a citizen of the United States,residing at New York, in the county of New York and State of New York,have invented certain new and useful Improvements in Power Systems forRadio Apparatus, of which the following is a full, clear, concise, andexact-description.-

This invention relates to power systems, and more particularly itrelates to power systems for radio apparatus of the type'ineludingvacuum tubes or other discharge devices having electrically heatedcathodes and designed for use'where economy of space and lightness areof prime importance, as in aeroplanes. A. great obstacle to radiotransmission from aeroplanes has been the weight of the power systemsrequired.

The primary object of this invention is to produce a power system forsuch radio apparatus which combines practical utility with the highestdegree of economy in space and weight.

With certain arrangements of vacuum tubes of the three-electrode typefor transmission of radio messages from aeroplanes, it is necessaryto'provide a filament heating source of approximately 10 volts and ananode-cathode source of from 200 to 600 volts. Both sources ofelectromotive force must be reasonably free from alternating currentcomponents and likewise must be of substantially constant voltage duringthe period required for signaling purposes;

otherwise continual manual adjustment as,

for example, by means of resistances, would be necessary.

In fulfilling the above and other requirements apparatus has beendesigned in accordance-.with the accompanying drawings in which 'Fig. 1is a conventional diagram of one embodiment of my invention; Fig. '2 is'a' diagram of a modified form; and Fig. 3 is '45 an explanatory diagramof the current filter'shown in both Figs. 1 and 2.

In Fig. 1 numeral 1 represents a suitable source of'electric energy,such as a storage battery adapted to give a considerable output atslightly above ten volts. Across battery 1 is connected the motorwinding of a dynamotor or motor-generator in which numeral 2 representsthe series -winding, 3' the shunt winding and 4 the armaturemechanically connected to the generator armature 5. In a preferred formall the windings are on a common armature. The generator 5 produces acurrent of sufiiciently high potential, for example, 500 volts, toprovide space current between the filaments 8 and anodes 9 of a set ofvacuum tubes 10. Across battery 1 are placed the filaments or cathodesof tubeslO in any suitable manner so that the cathodes may be heated.Associated with' the tubes 10 will be such elements as are necessary toconstitute a radio system of any desired kind. Since the details of suchsystems are known to'those skilled in the art, they are not hereinillustrated. Choke coil 12, such as is usually used in series with thesource of anode-cathode current in order to prevent high-frequencycurrents from'being short-circuited through the direct current source,is provided in conductor 6. Conductor 7 forms acommon negative terminal.

In the arrangement as so far described, the fluctuations induced by thereaction of the armature and by the commutator segments, particularlythe latter, will tend to create undesirable fluctuations of audiblefrequency in the output of the vacuum tubes 10. The commutator segments,for exam ple, w1ll tend to produce a fluctuation depending on theirnumber and speed of rotatute toogreat a bulk and weight to be carriedupon aeroplanes. A filter is here used consisting of inductance coils 13in series and resistances 14 across the line. Although less efficient inone respect since direct current energy is Wasted in the resistances,this. type of filter accomplishes the desired purpose and consists ofelements having mini-. mum bulk and Weight, and is much less expensive.

F or a particular description of the filter reference is made to Fig. 3.The direct current machine 4, owing to the action of its commutatorsegments, will act also as a source of superimposed alternating currentof, for example, 600 cycles, the direct current will pass throughandheat the filaments 8, but with some loss through the resistance! Ill 14.Suppose that the alternating voltages at points a, b, 0 and d arereEpectively represented by E E E and l that the impedances of coils 13to the said alternating voltages are respectively represented by Z Z andZ that the respective resistances of elements 14 are R and R and offilaments 8 is R then if Z Z etc. are large com- 'pared with R and Retc., the following equation will be approximately true:

2 Thus, for a given frequency, if R v Z1 R, E will be approximately 5The loss and R the alternating voltage minal voltage as it becomesdischarged, it

is necessary in some cases to compensate for this'by a ballastresistance 15' (Fig. 1). For this purpose it is desirable to use an ironwire sealed in an atmosphere of' inert gas in an airtight vessel, withthe terminals connected into the lO-volt circuit. When properlyconstructed the resistance of this device is comparatively high atmaximum battery voltage, but falls rapidly as the voltage decreasesslightly therefrom and hence tends to keep the voltage impressed acrossthe filaments substantially constant.

In Fig. 2 is shown a modified form in which the battery or source 1operates a motor-generatorwhich'has two output windings, one of tenvolts for heating the filaments, across which a filter 13, 14 is placed,as in the arrangement of Fig. 1, and a higher voltagewinding of 500volts for the anode-cathode current of the vacuum tubes 10. Themotor-generator of this arrangement is preferably a constant speedmachine,

and its output voltages will be substantiallyconstant at ten and 500volts, respectively. The device 15' of ig. 1 is therefore not needed inthis arrangement.

It should be noted that lightness andsmall volume are the features vwhich are considered of paramount importance in these systems, and areobtained at some sacrifice either of power efiiciency or of ability forsustained service over long periods, or both.

The arrangements shown are illustrative only, and other modificationsmaybe devised by those skilled in the art which will fall within the scopeof the invention as expressed by the appended claims. While described aspart of a transmitting system for an aeroplane, certain features of theinvention will be found useful in other places where a power plant oflimited weight and volume is required. Since the current discharge tubes10 may form elements of a receiving or high frequency generating systemin any of the known arrangements employing such devices, it is obviousthat the invention as applied to signaling stations is not limited totransmitting systems. Filters of the type shown are particularly usefulin receiving systems.

What is claimed is:

1. The combination with the elements of a thermionic vacuum tube systemwhich requires currents of high and low voltage respectively, for shortperiods of operation only, of a power system therefor comprising abattery of said low voltage, a motor operated by said battery, agenerator of said high voltage operated by said motor, and connectionsfrom said battery and said generator to said elements respectively.

2. In a radio system, a discharge device having a cathode, a source forsupplying current at a low voltage to heat said cathode, a generator,circuits whereby said source operates said generator, and circuitswhereby said generator supplies space current at a high voltage to saiddischarge device.

3. In a radio system, a dischar e device having a cathode, a battery andine concathode, a generator, circuits whereby said battery operates saidgenerator, circuits whereby. said generator supplies space current tosaid discharge device, and a. filter associated with said lineconductors comprising inductances in series with and a resistance inshunt to said cathode.

4. Ina system for radio communication, a source of current, meanswhereby said source supplies a high voltage to one path in said systemand a low voltage to another paththerein, said means reacting on said'ductors for supplying current to heat said second path to producefluctuating current therein, and a filter associated with said secondpath consisting of a number of inductances in series with and a numberof resistances in shunt to said path.

5. In combination in a radio system for use upon an aeroplane, abattery, a motorgenerator and, a vacuum tube, means whereby said batteryoperates said motor-generator, means whereby said battery supplies lowvoltage current to said tube, and means whereby said motor-generatorsupplies high voltage current tosaid tube.

6. In combination in a radio system for use upon an aeroplane, abattery, a motorgenerator and a vacuum tube, means where-- by saidbattery operates said motor-gen- "erator, means whereby said batterysupplies low voltage current to said vacuum tube, means whereby saidmotor-generator supplies high voltage current to said tube, means wherebsaid motor-generator reacts on said low vo tage supply, and means forrendering negligible the effect of said reaction.

7. In a signaling system the combination of two energy consuming loadpaths re- 10 quiring different voltages, at single source of energy forsupplying said paths, a direct connection between said source and one ofsaid paths, a direct current voltage transformer connected between saidsource and the other of said paths, means whereby said voltagetransformer causes an undesirable reaction upon one of said paths, and afilter forheliminating the eifect thereof upon said pat In Witnesswhereof, I hereunto subscribe 20 my name this 26th day of iikvpfil, A.D., 1918.

H. STOLLER.

